Middle-earth holds many strange mysteries and enigmas, but none quite so unusual as the River-maidens. These beautiful creatures, Man- or Elf-like in appearance, are born of the waters of secluded rivers. What they are exactly is unknown even to the Wise, but they are old and powerful.

Perhaps the best known of these is Goldberry, daughter of the Withywindle in the Old Forest on the borders of Buckland. She once tried to snare the equally mysterious Tom Bombadil, and though old Tom escaped her grasp, he eventually returned and took her to wife. Now together they dwell in seclusion in the Old Forest, away from the rest of the world. — lorebook

"'Come dear folk!' she said, taking Frodo by the hand. 'Laugh and be merry! I am Goldberry, daughter of the River.' Then lightly she passed them and closing the door she turned her back to it, with her white arms spread out across it. 'Let us shut out the night!' she said. (...) 'Fair lady Goldberry!' Frodo said again. 'Now the joy that was hidden in the songs we heard is made plain to me.

O slender as a willow-wand! O clearer than clear water!

O reed by the living pool! Fair River-daughter!O spring-time and summer-time, and spring again after!

O wind on the waterfall, and the leaves' laughter!'

"'Welcome!' she said. 'I had not heard that folk of the Shire were so sweet-tongued.'" — The Fellowship and the Ring